Concrete using Recycled Tyre Rubber

Engineers in Melbourne have recently discovered a technique that will replace 100% of conventional aggregates in concrete (such as gravel and crushed rock) with recycled tyre rubber that will meet building codes, promising a boost for the circular economy.

RMIT Universtity’s team (Professor Yu-Fei Wu, Dr Rajeev Roychand and Dr Mohammad Saberian) proposes that the new greener and lighter concrete may also lead to significant manufacturing and transportation costs, an exciting bonus!

At present, small amounts of rubber particles from types are being used to replace concrete aggregates however, previous attempts to replace 100% of the aggregates with rubber have lead to weak concrete products that have not met industry standards or building codes. This breakthrough promises to change all of that!

Published in the Resources, Conservation & Recycling journal, this recent study presents a manufacturing process for structural lightweight concrete where the traditional coarse aggregates in the mix are completely replaced by rubber from recycled car tyres.

“We have demonstrated with our precise casting method that this decades-old perceived limitation on using large amounts of coarse rubber particles in concrete can now be overcome. The technique involves using newly designed casting moulds to compress the coarse rubber aggregate in fresh concrete that enhances the building material’s performance.” 

Lead author and PhD researcher from RMIT University’s School of Engineering, Mohammad Momeen Ul Islam

Study co-author and team leader, Professor Jie Li, said this manufacturing process will unlock environmental and economic benefits for the construction industry.

“As a major portion of typical concrete is coarse aggregate, replacing all of this with used tyre rubber can significantly reduce the consumption of natural resources and also address the major environmental challenge of what to do with used tyres. This would benefit a range of developments including low-cost housing projects in rural and remote parts of Australia and other countries around the world.”

Study co-author and team leader, Professor Jie Li

In Australia, used types cannot actually be exported which means that creating new ways of recycling and reprocessing them that much more important. This development allows for a much greener and lighter concrete product that will have a massive impact on reducing manufacturing and transportation costs, allowing for more eco friendly work in construction.

What’s Next?

The team’s manufacturing process could be scaled up cost effectively within a precast concrete industrial setting in Australia and overseas, Islam said. Following successful testing in the workshop, the team is now looking into reinforcing the concrete to see how it can work in structural elements. We are most definitely eagerly awaiting more developments in creating a greener future for Australia’s construction industry!

Header Image: The RMIT team’s new casting technique generates structural lightweight concrete from used tyre rubber. Image: Mohammad Islam, RMIT

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